Ferrous base alloy for piercer points



Patented Aug. 9, 1949 2,478,723 Fac ors BASE ALLOY roe .PIERQEB TVPOINTS Jacob Trantin, Jr., Youngstown, Ohio;

N9 Dr n Thisqinvention relates to an alloy and more particularly to an alloy from which piercing points and plugs for use in seamless tube mills can be cast.

The principal object of the invention is the p ovision of an alloy particularly adapted for the formation of. piercing points and plugs for use in seamless tube mills.

A further object of the invention is the provision of an alloy from which piercing points and plugs can be cast and which piercing points and plugs in operation will have an unusually high resistance to picking up metal being pierced.

A still further object of the invention is the pr v i n of an alley fr m whi h pi r ing point a plu s for s amless tube mill use can be cas and which alloy includes an alloying ingredient capable of forming an oxide facilitating a metal piercing operation.

It is known that in the. manufacture of pipes and tubes, piercing points and plugs are commonly used for piercing billets to form seamless pipes and tubes. It is also known that many of the metals used for the formation of seamless pipe and tube are dimcult to pierce in billet form and that as a result an unusually high failure ratio occurs in connection with the piercing points and plugs utilized to perform the piercing operation.

The piercing points employed must have the ability to resist a change in contour which would seriously affect the wall thickness of the tube or pipe being formed, and, at the same time, must have the ability to pierce the billet without picking up portions of the billet by reason of adherence to the piercing plug used. The several objects of the invention and the ability to avoid the difficulties heretofore experienced with piercing points of various alloys are met in the present invention through the provision of an alloy from which piercing points and plugs may be formed and which alloy is capable of withstanding high thermal shock without deforming, cracking or otherwise becoming unsuitable for use, and, more importantly, capable of forming an oxide particularly resistant to pick up of metal of the billet being pierced. The scaling and physical properties of the alloy from which piercing points or plugs may be formed as by casting, makes it a satisfactory metal for use in piercing alloy steels of the high chromium and high chromium nickel type.

Scaling properties of the alloy disclosed herein are far superior to alloys heretofore known in the art and used for the formation of piercing points and plugs for seamless tube mills. The superior- Application Novemberlgfi, 1%6, ee!

izfl ilj l sr (01. 7511-124) 2 ity isfound in the ability of theallcy to form an oxide tightly adhering to the surface of the piercing point or plug, and which oxide will fuse or melt into a desirable lubricating. coating protecting the piercing point during. a piercing operation.

The piercing points formed of the alloy maybe of various shapes and sizes knownin the art, and as such they may comprise, for example, a point portion, a tapered'body portion and a sleeve or neck portion of a smaller diameter than the body portion, and be adaptable for. mounting on the end of a plug bar of the seamless tube mill.

The alloy is formed with 'a relatively largeper: centage of aluminum as one of the alloying mete als: The'high percentage of'thealuminum used in the alloy substantially contributes tothedesire able "properties found in. piercing points and plugs formed of the alloy. It is known that rel: ativel-y smallunu a -l minute quant ti s of aluminum have been included in various alloys for various purposes, some of which have been pro posed for use as piercing points or plugs for seamless tube mill operations. It is also known that the relatively small or minute quantities of aluminum heretofore used in such alloys have in no way contributed to the successful operation of the piercing points and plugs formed of the alloy.

The practice heretofore in the formation of alloys for piercing points and plugs has been to depend upon such alloying ingredients as chromium, copper and nickel to form a soft steel which will have satisfactoryscaling properties during use in piercing points formed of the alloy. Such alloys, however, have generally been incapable of repeated use as there is considerable distortion of the shape of the piercing points due to lack of uniform scaling properties.

The various objects of my invention are achieved by the composition of an alloy including about .20% to 1% carbon, molybdenum in eifective quantities up to 1.50%, about 8% to 30% chromium, and effective amounts of aluminum up to 3%, about 25% to 1.25% manganese, about 25% to 1.25% silicon, and vanadium in effective quantities up to 1% and copper in effective quantities up to 1.50%, and the remainder iron. The silicon and manganese are common in steel alloys and the alloy includes the usual percentages of sulphur and phophorus which in themselves are not objectionable.

It will be seen that the various objects of my invention are accomplished by the use of the steel alloy herein disclosed, emphasis being made to the relatively high percentage of aluminum and molybdenum.

A typical heat of the steel alloy of my invention possessing the several characteristics heretofore described may be seen in the following analysis: carbon .75%, molybdenum 1.50 chromium 18%, aluminum 2.75%, silicon 1%, manganese 1%, vanadium .50% and copper 1.25% and the remainder substantially all iron.

The steel alloy formed in accordance with the invention is of such nature as to lend itself particularly well to the formation of cast articles such as piercing points and plugs which may be used as integral parts of seamless tube mill equipment. It will be seen that effective amounts of aluminum are included in this steel alloy, and which amount of aluminum may be varied between a minimum efiective content and approximately 3%, it being observed that the aluminum content is relatively high in steel alloy practice and enables articles cast of the alloy to form an aluminum oxide over the wearing surface which is particularly desirable in piercing point operations primarily due to the ability of the alumi-- num oxide to resist the pick up of the metal of the billet being pierced as it forms an effective continuously replacing lubricating metallic coating.

It will thus be seen that the several objects of my invention are achieved by the provision of a castable steel alloy by including a relatively high percentage of aluminum, the physical characteristics of which may be altered by heat treatment and which alloy is particularly adaptable for the formation of piercing point and plugs as used in seamless tube mills due to the ability of articles cast from the alloy to form a protective aluminum oxide coating.

Having thus described my invention, what I claim is:

1. A steel alloy having an analysis including between about 20% to 1% carbon, between about .50% to 1.50% molybdenum, between about 8% to 30% chromium, between about 2% to 3% aluminum, between about .50% to 1.50% copper, between about .20% to 1% vanadium, between about .25% to 1.25% silicon, and between about .25% to 1.25% manganee, and the remainder all iron and including the usual percentage of sulphur and phosphorus, the said alloy being capable of being cast and being characterized by the ability to form an aluminum oxide coating and retain it under severe heat and abrasion conditions and to retain its cast shape under severe heat and abrasion conditions.

2. A steel alloy having about 75% carbon, about 1.50% molybdenum, about 18% chromium, about 2.75% aluminum, about 50% vanadium, about 1% silicon, about 1% manganese and about 1.25% copper, and the remainder all iron and including the usual percentages of sulphur and phosphorus, the said alloy being capable of being cast and being characterized by the ability to form and retain an aluminum oxide surface coating under severe heat and abrasion conditions and to retain its cast shape under severe heat and abrasion conditions.

JACOB TRANTIN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,237,379 Trantin Apr. 8, 1941 2,270,483 Trantin Jan. 20, 1942 FOREIGN PATENTS Number Country Date 721,934 France Mar. 9, 1932 

